Cincinnati-based Kroger said its adjusted net income, excluding charges, rose to $557 million, or $1.09 per diluted share. That compared with $481 million and 92 cents per diluted share for the same period last year, and easily topped Wall Street predictions.

Kroger shares closed up nearly 5.1% at $49.66.

The upbeat financial results were boosted by the $2.44 billion merger in which Matthews, N.C.- Harris Teeter Supermarkets became a Kroger subsidiary. Approved last year, the merger closed in late January, making this the first full quarter reflecting the deal's impact.

"Our strong first-quarter results set us up to deliver a 12%-15% net earnings growth rate for the year, partly due to the benefit of Harris teeter, compared to our long-term growth rate of 8%-11%, plus the growing dividend," said Kroger CEO Rodney McMullen. "We are pleased to start the year with growth momentum while also returning $1.1 billion in cash back to shareholders this quarter through our buyback program."

Kroger has more than 375,000 employees who work in 2,640 supermarkets and multi-department stores located in 34 states and Washington, D.C. The stores operate under two dozen local banner names, including Kroger, Dillons, Food 4 Less, King Soopers, Ralphs and Smith's.